Refrigeration machine with capacity control means



July 18, 1961 A. M. G. MOODY 2,992,543

REFRIGERATION MACHINE WITH CAPACITY CONTROL MEANS Filed March 21, 1958 4 Sheets-Sheet 1 2 2 R11 rm m1 1 LL LLLI LLLl Ll-Ll U 94 INVENTOR o ARTHUR MGMOODY 22 ATTORNEYS July 18, 1961 A M. cs. MOODY REFRIGERATION MACHINE WITH CAPACITY CONTROL MEANS Filed March 21. 1958 4 Sheets-Sheet I5 INVENTOR MOODY ARTHUR M. 6:

ATI'ORNEYS July 18, 1961 A. M. s. MOODY REFRIGERATION MACHINE WITH CAPACITY CONTROL MEANS Filed March 21, 1958 4 Sheets-Sheet 4 INVENTOR ARTHUR M. GMOODY ATTORNEYS United States Patent 2,992,543 REFRIGERATION MACHINE WITH CAPACITY CONTROL MEANS Arthur M. G. Moody, La Crosse, Wis., assignor to The Trane Company, Ila Crosse, Wis., a corporation of Wisconsin Filed Mar. 21, 1958, Ser. No. 722,945 6 Claims. (Cl. 62-196) This invention relates to a refrigerating machine and more particularly to a machine having a centrifugal compressor, a liquid cooler, a condenser and related auxiliary elements.

. It is an object of the invention to arrange the parts of the machine into a simple compact unitary structure.

It is another object of the invention to provide a hermetic construction having the motor mounted within the casing in such a manner that no seal between the interior of the casing and the exterior is required.

It is another object of the invention to provide a simple and efiicient mechanism for reducing the capacity according to the needs for refrigeration.

It is another object of the invention to provide an effective distribution of liquid to the evaporator and an effective means for withdrawing the gas from the evaporator.

It is another object of the invention to eliminate the usual compressor scroll and to discharge the gas directly to the condenser surfaces.

It is another object of the invention to discharge the gas from compressor at an angle to the fins of the condenser thereby increasing the heat transfer due to turbulence.

It is another object of the invention to provide an arrangement in which the gas flows upwardly over the surfaces of the condenser thus transferring heat to condensed liquid which is dropping down to the bottom of the condenser chamber.

Other objects and advantages of the invention will be apparent from the detailed description taken in connection with the accompanying drawings in which:

FIGURE 1 is a vertical elevational view of the machine;

FIGURE 2 is a top plan view of the machine;

7 FIGURE 3 is a cross-sectional view taken on line 3-3 of FIGURE 2;

FIGURE 4 is a cross-sectional view taken on line 44 ofFIGURE 3;

FIGURE 5 is a cross-sectional view taken on line 5-5 of FIGURE 4;

. FIGURE 6 is a cross-sectional view taken on line 6-6 of FIGURE 3;

FIGURE 7 is a vertical elevational view of the control mechanism; and

FIGURE 8 is a view partly in section taken on the line 8-8 of FIGURE 7.

Referring now to FIGURE 1, the machine has an upper casing 10 containing a compressor designated gen erally by the numeral 12, a driver for the compressor designated generally by the numeral 14, and a condenser indicated generally by the numeral .16. The machine has a lower casing 18 containing an evaporator designated generally by the numeral 20. The upper casing 18 and the lower casing 18 are held in sealing engagement in any suitable manner as by bolts 22. The interior of the machine is charged With a suitable amount of a suitable refrigerant such as refrigerant 11. The machine is supported on legs 23 secured to the lower casing 18.

The driver 14 has an electric motor 24 which is connected to a suitable source of electricity. The motor shaft 26 has a gear 28 which is in driving engagement with a pinion 30 mounted on a pinion shaft 32. The

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motor shaft 26 is rotatably supported in bearings 33 in an inner housing 34 and the pinion shaft 32 is rotatably supported in bearings 35 in the inner housing 34. The inner housing 34 and the motor 24 are in sealed engagement with an adapter ring 37. The adapter ring 37 is in sealed engagement with an outer housing 36 which in turn is in sealed engagement with the upper casing 10. A reservoir 38 of lubricating fluid is contained in the outer housing 36. An impeller 40 of the centrifugal type is mounted on the shaft 32 to rotate therewith. A wall 42 is secured to the outer housing 36 and to the upper casing 16. Wall 42 separated the interior of the upper casing 10 from the interior of the lower casing 18. The wall 42- and the outer housing 36 provide a shroud for the impeller and a diffusing passageway 43 for the gas discharged by the impeller 40.

The condenser 16 is mounted in an annular condensing chamber 44 and has an inlet header 45, an outlet header 46, and a plurality of tubes 48 wound upon themselves and having their ends in fluid communication with the inlet header 45 and the outlet header 46. Cooling water is circulated through the tubes 48 of the condenser 16. The tubes 48 have extended heat transfer fins 5i) mounted thereon.

The gas flows from the dilfusing passagway 43 with a tangential velocity component and therefore impinges on the fins 50 at an angle with respect to the fins. This angular impingement creates turbulence in the gas and increases the heat transfer.

With the major portion of the condenser 18 above the diffusing passageway 43 the gas flows generally upward over the condenser and transfers its super heat to the condensed liquid dripping downwardly. The capacity of the condenser is thereby increased. The latent heat in the gas is transferred through the fins 16 and tubes 48 to the cooling water.

The condensed liquid falls to the bottom of the casing 10 and flows through a conduit 54 to the lower casing 18. A nozzle 56 is connected to the conduit 54 and directs the flow of liquid at a small angle with respect to the wall of the casing 18. The liquid discharged by the nozzle 56, therefore, flows in a vortex around the casing 18 and the gas created by the reduction in pressure has an opportu nity to separate from the liquid. The liquid now free from the flash gas flows down over baffles 57 and 58 to the evaporator 20.

The evaporator 20 has an inlet header 60, a discharge header 62 and a plurality of tubes 64 extending between and in-fiuid communication with the inlet header 6t) and the outlet header 62. The tubes 64 preferably have a plurality of heat transfer fins 68 in heat transfer contact therewith. In place of the tubes 64 and the heat transfer fins 68, other types of surface such as tubing having an integral extruded fin might be used. The liquid refrigerant flowing down over the evaporator 20 removes heat from the fluid circulated in the tubes 64 and in turn is evaporated by receiving said heat. The evaporated gas rises and flows past the batfies 57 and 58. The gas then flows through a liquid eliminator 59 which has a closely packed screen which prevents entrained droplets of liquid from passing through. From the eliminator 59' the gas flows into an inlet cone 70 which conducts the gas to the inlet of the impeller 40.

In order to balance the thrust on the impeller, a chamber 70 between the impeller 40 and the outer housing 36 is sealed by labyrinth 72. A conduit 74 extends between the chamber 70 and the inside of the lower casing 18 so that the chamber-70 is maintained at a pressure equal to that in the evaporator casing 18.

Means for regulating capacity of the machine will now be described.

- The wall 42 has a tangential passageway 7 6 which communicates with an annular chamber 73. Annular chamber 78 is in fluid communication with the inlet 79 to the impeller 49. A valve 80 controls the flow of gas from the condensing chamber 44 to the tangential passageway 76. The opening 82 in the valve 80 has angularly extending sides to provide substantially uniformly increasing flow according to the amount that the valve is moved from closed position. The valve 80 is connected by a link 84 to a. lever 86 which is pivotally mounted at 88 to the upper casing 10. A bellows 90 and a plate 91 provide a seal between the lever 86 and the casing 10. The lever 86 is connected by pivoted links M and 93 to a position-ing motor 94 which is shown diagrammatically and which may be of the well known fluid or electric type. The motor 94 is supported on the upper casing by a bracket 95. The positioning motor 94 is connected by a line 96 to a proportional thermostat 97 which has a temperature sensitive element 99 in the outlet chilled water header 62.

An electric thermostat is used when the positioning motor is electric and a fluid thermostat is used when the positioning motor is of the fluid type. The positioning motor 94, the proportional thermostat 97 and the element 99 operate in such a manner that upon a rise in temperature of the chilled water in outlet header 62, the amount of movement of the motor 94 and the valve 80 is proportional to the deviation of the water temperature from the temperature setting of the thermostat 9'7. When the valve 80 is in closed position, no refrigerant gas is bypassed from. the interior of the upper chamber to the inlet of the impeller 46 and the machine will operate at its full capacity.

When conditions indicate that less than full capacity is required to set the needs for refrigeration, the motor 94 moves the lever 86 which in turn through the link 84 raises the valve 80 to permit refrigerant gas to flow through the tangential passageway 76 and into the inlet 79 of the impeller 40. Inasmuch as the passageway 76 is tangential to the annular chamber 78, the refrigerant gas flowing therefrom mo es in a spiral in the direction of rotation of the impeller 40, and the impeller 40 is able to do less work on the gas. Therefore, the impeller 40 is able to compress a lesser volume of refrigerant gas than when the machine is operating at full capacity. Since the impeller 4t compresses a lesser volume of refrigerant gas, the refrigerating output of the machine is correspondingly reduced.

1 claim:

1. A refrigerating machine comprising an upper casing, a lower casing in sealed engagement with said upper casing, a wall separating the space of said upper casing from the space of said lower casing, refrigerant fluid in said upper and lower casings, a motor sealed in said upper casing, a centrifugal impeller rotatably mounted in said upper casing and operatively connected to said motor to be rotatably driven thereby, said centrifugal impeller having an inlet arranged to receive refrigerant fluid from said lower casing through an opening in said wall and to discharge said refrigerant into said upper casing, a condenser in said upper casing, an evaporator in said lower casing, means for conducting refrigerant liquid from said upper casing to said lower casing, means for discharging refrigerant gas from said upper casing to the inlet of said compressor in a vortex having an axis of rotation substantially in alignment with the axis of'rotation of the impeller and a direction of rotation corresponding to the direction of rotation of the impeller and means for controlling said last mentioned means to vary its effectiveness in discharging gas.

2. A refrigerating machine comprising an upper casing, a lower casing in sealed engagement with said upper casing, a wall separating the space of said upper casing from the space of said lower casing, refrigerant fluid in said upper and lower casings, a motor in said upper casing, a centrifugal impeller rotatably mounted in said upper casing and operatively connected to said motor to be rotatably driven thereby, said centrifugal impeller having an outlet in said upper casing to discharge refrigerant into said upper casing, said impeller having an inlet extending into an opening through said wall to receive refrigerant from said lower casing, a condenser in said upper casing, an evaporator in said lower casing, means for conducting refrigerant liquid from said upper casing to said lower casing, said wall having a substantially annular chamber substantially in axial alignment with the axis of rotation of said impeller and in fluid communication with the inlet of said impeller, means for conducting refrigerant gas from said upper casing tangentially into the annular chamber to produce in the annular chamber a vortex having a direction of rotation the same as that of said impeller and means for varying the rate of flow in said refrigerant gas conducting means to vary the rate of flow through said impeller.

3. A refrigerating machine comprising an upper oasing, a lower casing in sealed engagement with said upper casing, a wall separating the space of said upper casing from the space of said lower easing, refrigerant fluid in said upper and lower casings, a first motor in said upper casing, a centrifugal impeller rotatably mounted in said upper casing and operatively connected to said first motor to be rotatably driven thereby, said centrifugal impeller having an outlet in said upper casing to discharge refrigerant into said upper casing, said impeller having an inlet extending into an opening through said wall to receive refrigerant from said lower casing, a condenser in said upper casing, an evaporator in said lower casing, means for conduct-ing refrigerant liquid from said upper casing to said lower casing, said wall having a substantially annular chamber substantially in axial alignment with the axis of rotation of said impeller and in fluid communication with the inlet of said impeller, said wall having a passageway from said upper casing and communicating substantially tangentially with the annular chamber to conduct refrigerant gas from said upper casing to said chamber to produce in the annular chamber a vortex having a direction of rotation the same as that of said impeller, a valve for con-trolling the flow of refrigerant gas in the passageway, a second motor for positioning said valve, means for controlling said second motor responsive to the temperature of the evaporator.

4. A refrigerating machine comprising an upper casing and a lower casing forming a closed chamber, refrigerant in said chamber, a motor in said upper casing, a centrifugal compressor mounted in said upper casing and operatively connected to said motor to be driven thereby, said compressor having its inlet in fluid communication with said lower casing and its discharge in fluid communication with said upper casing, a condenser in said upper casing to condense gaseous refrigerant discharged by said compressor, vertically disposed headers mounted in said lower casing, two series of parallel tubes extending in expanding spiral conformation from each of said headers, the tubes of one series being in overlapping relationship with the tubes of the other series, means connecting the tubes of one series with the tubes of the other series at their ends remote from the headers, means for conducting liquid refrigerant from said upper casing to said lower casing and in heat transfer relationship to said tubes to cool heat transfer fluid in said tubes.

5. A refrigerating machine comprising outer housing, an upper casing surrounding said outer housing and co operating therewith to define an annular condensing chamber, an evaporator casing secured to said upper casing, refrigerant in said upper casing and said evaporator casing, a wall separating the space of said upper casing from the space of said evaporator casing, said Wall cooperating with said outer housing to form an impeller housing having an opening in fluid communication with said evaporator casing and an annular discharge passageway open at its periphery to said annular condensing chamber, a substantially annular condenser mounted in said annular condensing chamber and having heat transfer fins extending in planes substantially radial to the axis of said annular condensing chamber, a motor in said outer housing, a centrifugal impeller rotatably mounted in said impeller housing and connected to said motor to be rotatably driven thereby to draw gas from the evaporator casing through said opening and to discharge the gas outwardly from the periphery of the impeller with radial and tangential components of velocity whereby the gas discharged impinges upon said fins at an angle with respect to the planes of said fins and thereby increases the heat transfer rate from the gas to said fins, and means for conducting refrigerant from said annular condensing chamber to said evaporator casing.

6. A refrigerating machine comprising a substantially cylindrical upper casing, a substantially cylindrical lower casing in sealed engagement with said substantially cylindrical upper casing, a wall separating the space of said upper casing from the space of said lower casing, refrigerant fluid in said upper and lower casings, an annular condenser in said upper casing and extending substantially the height of said upper casing, said annular condenser being adapted to be connected to a source of cooling fluid an evaporator in said lower casing, a motor in said upper casing, a centrifugal impeller rotatably mounted in said upper casing and operatively connected to said motor to be rot-atably driven thereby, said centrifugal impeller having an inlet arranged to receive refrigerant gas from said lower casing through an opening in said wall and to discharge said refrigerant gas into said upper casing against the lower third portion of said condenser whereby the refrigerant gas flows upwardly over the condenser and transfers heat to the condensed liquid refrigerant dripping from the condenser, and means for conducting refrigerant liquid from said upper casing to said lower casing.

References Cited in the file of this patent UNITED STATES PATENTS 1,575,818 Carrier Mar. 9, 1926 1,725,472 Orr Aug. 20, 1929 2,715,992 Wilson Aug. 23, 1955 

